An aircraft crewman, particularly in military aircraft, is equipped with a variety of restraint, recovery and life support systems which are principally utilized while the aircraft is in flight and in the event of the necessity for an emergency evacuation, particularly at high altitudes from fast moving aircraft. The crewman conventionally wears a harness which fits over his back and shoulders with a chest strap connecting the upper portion of the shoulder straps and leg straps which wrap around the legs and thighs of the wearer. Such a harness commonly referred to as a parachute harness, additionally supports terminals for oxygen and communication systems, as well as coupling devices for securing to the harness the parachute canopy risers, shoulder restraint straps and survival kit straps. The survival kit conventionally is contained in the seat portion of the aircraft seat structure and, by being secured to the crewman's parachute harness, is retained by him in the event of an emergency evacuation by seat ejection, followed by parachute landing. Also included in the restraint system is a conventional seat or lap belt together with leg restraints securing the crewman's legs to the seat structure, and sticker clip straps which releasably secure the survival kit straps and thus the connected harness to the seat structure.
In the event of an emergency evacuation while the aircraft is in flight, the entire ejection seat and restraint system, including the parachute and survival kit is power ejected from the aircraft. At an appropriate time after the seat is safely away from the aircraft, and the crewman and seat unit is at or has descended to a safe altitude, the seat restraints are automatically disengaged allowing the crewman to descend safely by means of the parachute secured to the shoulder straps of his harness and carrying with him the survival kit secured to the harness. Life support systems, particularly emergency oxygen, are carried with the ejection system and the oxygen is supplied to the crewman's oxygen mask through the harness mounted coupling system.
As an added safety feature, in the event the automatic seat restraint disengagement procedures are not accomplished, the aircraft seat conventionally includes manually actuated devices for releasing the seat and leg restraints allowing the seat to fall away and for performing several other functions so that the crewman can pull his ripcord and descend by parachute.
After a parachute landing, under some circumstances it is desirable for the person to quickly divest himself of the parachute harness. To this end, parachute harness release systems have been designed, an illustrative one of which is shown in U.S. Pat. No. 3,658,281 issued Apr. 25, 1972, to J. A. Gaylord for "Single Release For Parachute Harness." The Gaylord system releases the complete parachute harness, including the survival kit carried thereby, and is intended for divestment of the complete parachute harness after landing from an emergency evacuation from a moving aircraft and parachute descent. Once safely on the ground, the wearer usually discards the parachute harness. Therefore, there is no need in the Gaylord structure to disconnect the survival kit from the harness proper. Further, once on the ground, there is little if any need for a harness release system which can be quickly reconnected should the crewman decide that he wishes to retain and wear the harness.
It will be appreciated that once a crewman has positioned himself in an aircraft, engaged his harness with his oxygen, communication and life support systems, engaged the seat shoulder straps and parachute risers, engaged the seat lap belt and leg restraints, and engaged the survival kit straps, he is effectively integrated into and fully restrained within the aircraft cockpit. There is still, however, a substantial danger, particularly for combat aircraft, of fire or other emergency occurring during start-up, take-off or after landing, or while the aircraft is on the ground or water, necessitating immediate evacuation by the crewman from the aircraft. While under some circumstances it is possible to initiate the ejection seat while the aircraft is on the ground, the risk of injury by utilizing that procedure is substantial.